1. Field of the Invention
The present invention relates to optical connectors and, especially, to an optical connector having an optical element such as an attenuator or filter.
2. Description of the Related Art
Japanese patent application Kokai No. 2000-221326 discloses an optical connector having an attenuator or filter for attenuation or filtering function. As shown in FIGS. 7 and 8, this optical connector 1 comprises a housing 2, an optical element or attenuator 3 incorporated in the housing 2, an aligning sleeve 4 put over the attenuator 3 from the base side of the attenuator, and a body member 5 connected to the attenuator 3 via the aligning sleeve 4.
The housing 2 is made from a synthetic resin in the form of a cylinder and has a J-shaped engaging slot 6 provided in the side wall and a through-hole 7 in the axial direction. Also, it has first and second step portions 8 and 9 to form front, middle, and base sections 10, 11, and 12, respectively, so that the diameter of the through-hole 7 increases in a stepwise fashion.
The attenuator 3 comprises a ferrule for holding an optical fiber 13a having an attenuation function and an annular stopper member 15 attached to the central area of the ferrule 14. The stopper member 15 is made of a metal, for example, so as to have an outside diameter greater than the front section 10 but smaller than the middle section 11 and an identification mark on the outside surface to identify the attenuation characteristics and model No. of the attenuator 3. The aligning sleeve 4 has a cylindrical form and a slit in the axial direction to provide elasticity.
The body member 5 comprises an insulated cable 16, a fixing metal 17 for fixing the front portion of the insulated cable 16, a crimping metal 18 for fixing by crimping the insulated cable 16 to the fixing metal 17, a ferrule 19 for holding the front portion of an optical fiber 13b or another optical element, a sliding sleeve 20 fixed to the base side of the ferrule 19, and a coil spring 21 provided between the sliding sleeve 20 and the fixing metal 17 to bias the ferrule 19 forwardly. The fixing metal 17 has such a shape that it is fitted in the middle section 11 of the housing 2 and a projection 22 on the outside surface for engagement with the engaging slot 6.
To assemble such an optical connector 1, the attenuator 3 is put into the through-hole 7 through the base side of the housing 2, and the aligning sleeve 4 is put over the base side of the ferrule 14. Then, the body member 5 is pushed into the housing 2 such that the projection 22 engages the engaging slot 6. As a result, the fixing metal 17 fits in the middle section 11, the ferrule 19 fits in the base side of the aligning sleeve 4, and the front end of the stopper member 15 abuts on the first step portion 8. Then, the body member 5 is further pushed into the housing 2 such that the ferrule 19 abuts face-to-face on the ferrule 14 of the attenuator 3 so that the optical fibers 13a and 13b are connected to each other and the ferrule 19 is slid toward the base side along with the sliding sleeve 20 against the coil spring 21. Then, when the housing 2 is rotated in the predetermined direction and the pushing operation is terminated, the coil spring 21 brings the housing 2 toward the front side so that the projection 22 engages the engaging slot 6 to lock the body member 5 to the housing 2.
The above optical connector, however, requires a large amount of work for replacing the attenuator 3. That is, each of the attenuator 3, aligning sleeve 4, and body member 5 is removed from the housing 2 and, then, a new attenuator is put into the housing 2, followed by reassembling the aligning sleeve 4 and body member 5. In addition, the attenuator 3 is so small that it is difficult to read the identification mark, frequently resulting in the installation of a wrong attenuator or the loss of a replacement attenuator.
Accordingly, it is an object of the invention to provide an optical connector enabling to simplify the replacement operation and increase the efficiency of the operation.
According to the invention there is provided an optical connector, comprising a housing; an optical element provided in the housing; retaining means for preventing separation of the optical element from the housing so that the optical element can be replaced together with the housing as a unit; the retaining means comprising a stopper member; an abutment portion provided on the housing for abutment with one end of the stopper member to restrict movement of the optical element toward one end of the housing; a retaining member secured to the housing for abutment with the other end of the stopper member to restrict movement of the optical element toward the other side, thereby preventing the optical element from falling off from the housing.
It is preferred that it further comprises an aligning sleeve for aligning and holding the optical element and another optical element to be connected to the optical element and enabling to replace the optical element together with the housing and the aligning sleeve as a unit.
It is further preferred that the retaining member is made such that it is press-fitted into the housing from the other side of the stopper member, it is screwed into the housing from the other side of the stopper member, or that it is inserted into the housing through a slot in a side wall of the housing.
Since the optical element is made such that it is replaced together with the housing as a unit, the replacing operation is simplified, leading to the increased efficiency of the operation.